How Do I Find Nearby App Users In Android?

I am making an application which needs to be able to find people nearby, who are users of my app. I looked at many answers of precedent similar questions, and it seems I have no ch

Solution 1:

To find nearby users efficiently, you need a spatial index. See: Hierarchical Triangular Mesh.

You also can use one of the databases that support spatial queries.

I'll probably send latitude and longitude information or address information to the server. Can't I compare those strings with all users' address list from the first numbers or letters using string searching algorithms or something?

That won't work with latitude and longitude because that way you can only search for proximity in one dimension. For example, 30°N 30°E will appear closer to 30°N 90°E than to 31°N 30°E.

It may work with addresses, but only if they are reliably connected with coordinates (i.e. not typed in by users), and only if you don't mind that users 200 meters apart but on different sides of some administrative border will not count as close to each other.

Solution 2:

You can use the REST Api from Server Side using PHP which takes the Current LAT LONG of all user for your app From User's Android Phone at certain time Interval Lets Say 5 min & it returns the Nearest Location,Address Distance.You need to call the Api @ certain time Interval & in response From Server You will get all the Details What You Want Like Nearest Location of Your App user, Distance and Other Thing.

Why i am suggesting this way because to do Computation from Android Side Will Affect the App Performance Having Battery Issues So its better to Have All computation from Server side instead of Android(User) Side

hope this will helps you.

Solution 3:

I am a bit late here but for anyone who comes across this question, assuming you are using Firebase for your database, your best option would be GeoFire using queries around a specific point in coordinates and a radius in km. Here is a link to the github repo https://github.com/firebase/geofire-android which explains everything in detail.